The invention relates generally to commercial and residential heating ventilation and air conditioning (HVAC) filtration, and more specifically to a collapsible filter that is collapsed to reduce shipping volume and is readily constructed by the end user.
Traditional pleated filters for commercial and residential HVAC systems include one or more frame members and a pleated filtration media glued to the frame members. As is known in the field, the filtration media is pleated to provide greater surface area on which to collect particulate. The greater surface area takes longer to clog the pores of the media with particulate, thereby prolonging the life of the filter media. Furthermore, pleated media tends to be stronger than planar media in resisting deformation due to the force of air passing through the media. However, pleated filters occupy a large volume of empty space per filter due to the shape of the pleated media. While such filters have low weight, they tend to be expensive to transport when considering them on a per unit volume basis due to the large amount of empty space per unit volume.
It is known to construct filters of materials that are collapsed by the manufacturer and assembled by end users. Such filters have significantly reduced shipping volumes, but require the end user to expand and construct the finished filter so that it can be used in a conventional manner. Conventional collapsible filters require the filter components to depart significantly from traditional non-collapsible filter components at a significant cost disadvantage. U.S. Pat. No. 3,938,973 discloses such a prior art collapsible filter, and includes a pinch frame furnace filter that requires a combination of framing materials including heavier paperboard, expensive plastic components and/or adhesive for the end user to assemble. There is also a higher tooling cost with the plastic components, because such components lead to less flexibility on filter sizes available.
The need exists for an improved collapsible filter that permits an end user to expand and construct the finished product rapidly, with minimal skill requirements and without the prior art's cost disadvantages.